Methods of air distribution through elongated slots



March 29, 1966 AVERlLL ET AL 3,242,847

METHODS OF AIR DISTRIBUTION THROUGH ELONGATED SLOTS 2 Sheets-Sheet 1 Original Filed April 9, 1965 1 L nlv T a m m 5 M .0 R I In? E 3 v n, w A //I 9 T1 F m M f i M El l E a T 9 m G U 2 E H 2 9 4 i 9 I ilrfliinifliflliflfr 2 m 3 8 Q 2 l m C! O l 3 n v 3 2 7 i A A 2 p A. J g z a 6 I u i EI w w 2+ 2 HAROLD E. S RAUB March 29, 1966 AVER|| ET AL 3,242,847

METHODS OF AIR DISTRIBUTION THROUGH ELONGATED SLOTS 2 Sheets-Sheet 2 Original Filed April 9, 1963 FIG. 3

FIG.4

FIG.5

I I ll wl R WE NV EA W AF E N E G U E HAROLD E. STRAUB United States Patent 3,242,847 METHODS OF AIR DISTRIBUTION THROUGH ELONGATED SLOTS Eugene F. Averill, Waterloo, and Harold E. Strauls, Cedar Falls, Iowa, assignors to Titus Manufacturing Corporation, Waterloo, Iowa, a corporation of Iowa Original applications Apr. 9, 1963, Ser. No. 271,728, now Patent No. 3,185,068, dated May 25, 1965, and Ser. No. 271,729, new Patent No. 3,183,821, dated May 18, 1965. Divided and this application Apr. 29, 1965, Ser. No. 451,939

5 Claims. (Cl. 98-40) This application is a division of our copending applications Serial Nos. 271,728 and 271,729, both of which were filed on April 9, 1963, now Patent Nos. 3,185,068 and 3,183,821, respectively.

This application pertains to methods of air distribution disclosed in the aforesaid, concurrently filed applications, i.e., methods for distributing air from a duct through an elongated slot or slots of a diffuser mounted in the ceiling of a room or other enclosure.

The types of slot diffusers involved are ones having spaced, opposite, elongated walls defining an elongated air flow channel with horizontal, elongated, inwardly directed, substantially co-planar, spaced lips at the downstream, lower ends of said channel. The lips define in the space therebetween an elongated, unobstructed, horizontal air discharge slot.

The improvements provided by this invention relate to feeding an air stream from the duct downwardly into the upper side of said channel to provide an air stream flowing transversely to the longitudinal axis of the channel. This air stream is split in the channel into two, side-by-side, downwardly flowing air streams flowing along opposite sides of the channel. The respective, divided air streams are impinged against the upper side of the respective lips at the downstream or lower side of the air flow channel, thereby deflecting the respective, divided air streams laterally across said slot.

The respective flow volumes of the divided air streams are dampered between (a) substantially equal flow volumes whereby the laterally deflected, divided air streams reunite at said slot and emerge into the upper part of the room in an essentially vertically downward flow pattern and (b) substantially complete blocking of air flow through only one of said divided air streams whereby the other divided, flowing air stream is deflected laterally across said slot and emerges into the upper part of the room in an essentially horizontal pattern.

In the practice of the invention, the divided air streams are dampered to provide substantially equal flow volumes when the temperature of the air fed into the upper part of the channel of the slot diffuser is higher than the temperature of the room air. The result is an essentially vertically downward flow pattern from the slot into the room. On the other hand, the divided air streams are damper-ed to block off essentially all flow of one of the divided air streams when the temperature of the supply air is lower than the temperature of the room air. This damper setting gives an essentially horizontal air flow pattern from the slot into the room.

More specifically, when the air supplied to the diffuser is warm air, the best air discharge pattern usually is a vertical pattern, i.e., one in which the diffuser air discharge stream is directed outwardly at right angles to the face of the diffuser and the ceiling in which it is mounted. Warm air, being lighter or less dense than colder air, is best directed into the room at right angles to the ceiling to mix it with the cooler air in the lower areas of the room to Warm the latter.

On the other hand, when the air supplied through the diffuser is cool air, the best air discharge pattern usually is a horizontal pattern, i.e., one in which the air stream or streams are directed laterally outwardly from the diffuser substantially parallel with the face of the diffuser and the ceiling. The greater density of cool air causes it to fall or descend into a body of warmer air. This makes the horizontal pattern the most desirable because the cool air can be spread across the ceiling or a portion thereof. It falls as its velocity drops and ultimately mixes with and cools the Warmer air in the lower areas of the room. If a vertical pattern were used with a cool air discharge stream, drafts causing discomfort to occupants of the room may result. Also, the horizontal pattern provides a more even distribution of the cooling air throughout the room and thereby keeps the room temperature more uniform throughout.

The new methods of air distribution of the invention are illustrated in the drawings wherein:

FIGURE 1 is a bottom plan view of one embodiment of slot diffuser;

FIG. 2 is a section view taken on section 22 of FIG. 1 and shows the methods for obtaining a vertical pattern (the left-hand slot) and for obtaining a horizontal pattern (the right-hand slot);

FIG. 3 is a broken, perspective view of the damper used in FIGS. 1 and 2;

FIG. 4 is a section of a single slot diffuser with an elongated, cylindrical, longitudinally split duct (shown in fragment) mounted thereon;

FIG. 5 is a section similar to FIG. 4 with another type of duct (shown in fragment) mounted on a single slot diffuser (also shown in fragment);

FIG. 6 is a cross-sectional view like that of FIG. 2, but showing the air pattern controllers in position to provide a two-way, horizontal or lateral air discharge pattern;

FIG. 7 is a transverse cross-sectional view, similar to the sectional view of FIG. 2, of another embodiment of a double slot diffuser of the invention;

FIG. 8 is a transverse cross-section of a single slot diffuser of the invention mounted in an elongated opening of a ceiling (shown in fragment) with the damper set for a vertical pattern;

FIG. 9 is a bottom plan view of another embodiment of a slot diffuser; and

FIGS. 10-12 are sections taken on section 10-10 of FIG. 9 and show methods for obtaining vertical and/or horizontal patterns with this embodiment.

Briefly, the slot diffuser embodiments of FIGS. 1-8 provide selective air discharge patterns through the use of elongated, spaced, side walls defining therebetween one or more air flow channels. These channel(s) have at their downstream side opposing, inwardly directed lips defining an elongated slot and are employed to deflect air directed thereagainst laterally as it flows through the elongated, air discharge slot or slots. By providing a movable damper member or air pattern controller in each channel to direct air flow through one-half, the other half, or both halves of the channels, a variety of air discharge patterns can be selected.

The air flow controller preferably is an elongated, pivotally mounted plate or vane located in each channel. It is adapted to be pivoted to block off selectively one side or the other side of the channel whereby air flowing through the channel is directed against one or the other of the elongated lips at the downstream end of the channels whereby the latter lip deflects the air stream into a lateral or outward air discharge stream, an air discharge pattern often referred to as a horizontal pattern. When the air pattern controller is in a neutral or nonblocking position, the air flows through both halves or sides of the air channels with the result that the discharged air pattern is a vertical pattern.

Referring to the drawings, there is shown in FIGS. 1 and 2 a double slot diffuser 1 having in the face thereof a pair of substantially parallel, elongated air discharge slots 2, 3. The diffuser 1 comprises three elongated spaced sections 4, and 6, which are extruded members having the transverse cross-sections shown in FIG. 2. Sections 4 and 5 may be identical extrusions, one being in assembly of the diffuser the mirror image of the other. The sections 4, 5 comprise a longitudinal wall 7 comprising a straight wall segment 8 at the upstream side of the diffuser, a circularly curved wall segment 9 depending therefrom, and an outwardly-directed flange 10 at the downstream edge of the curved wall segment 9. The flanges extend laterally outwardly along each edge of the diffuser, and the outermost edges lie against the marginal portions of the ceiling or wall around the opening in which the diffuser is mounted.

The wall 7 forms with lateral wall 11 and parallel wall 12 an elongated channel 13 opening upwardly. Air conductors or adapters (not shown) which connect the air supply duct (not shown) and diffuser, may be mounted in the channels. 13. The lower surface of wall 11 and the upper surface of flange 10 have longitudinally-extending lips 14, 15, 16 and 17. The lip pairs 14, and 16, 17 form longitudinal grooves in which may be seated the opposite edges of diffuser mounting plates 18, 19, to which may be attached clips or brackets (not shown), which, in turn, are attached to hangers in the case of suspended ceilings or structural members of the ceiling or wall itself. Also, in case the diffuser layout calls for two or more abutted, aligned diffuser sections like that of FIG. 1, the plates 18, 19 may extend between abutted diffuser sections to provide proper alignment between abutted sections.

The center section 6 of the diffuser is an extruded, hollow section made of a top wall 20, a bottom wall 21, and side walls 22, 23. The side walls 22, 23 have a circular, concavely-curved wall segment 24, 25, respectively. Curved wall segment 24 has substantially the same radius and center of curvature as concave wall segment 9 of the section 4, and curved wall segment 25 has a similar relationship to concave wall segment 9 of section 5thereby defining a pair of substantially cylindrical, elongated air passage channels 26, 27.

Each substantially cylindrical passage 26, 27 has an air pattern controller or damper 28, 29, each of which comprises a cylindrical rod 30 and .an elongated plate 31 extending radially therefrom. The rod 30 may be located substantially at the radial center of the cylindrical passages 26, 27, whereby the air pattern controllers 28, 29 may have pivot axes substantially common with the longitudinal axes of cylindrical passages 26, 27. The radial outer edges of plates 31 extend slightly beyond the inner faces of walls 9, 24 and 25, and the air controllers 28, 29 are 'pivotable between the upstream portions of wall pairs 9, 24 and 9, 25. These walls may have offsets 33 forming limit shoulders 34 forming stops against which the edges 32 of the controller abut. The ends 35 of rods 30 may be pivotally supported in end walls 36, 37 of the diffuser, which, in turn, are attached to the ends of sections 4, 5 and 6 to provide a unitary structure. Where the air controller 28 and/or 29 is of a length whereby it needs intermediate support against bowing, any suitable support may be provided along the length of the air controller 28 and/or 29, as needed.

When air is supplied through the upstream side of the diffuser, it enters channels 26, 27 between lips 42, 43, 44 and 45, and it may be deflected into several patterns depending on the position of the air pattern controllers 28, 29. When the controller is rotated to one side or the other of the passage, e.g., as shown in the channel 27 of FIG. 2, the air stream is deflected against the curved wall of the opposite side of the channel. It flows in a curved path through the channel and is discharged from the slot in a laterally outward stream. The lips 46, 47, 48 and 49 formed by the downstream edges of curved walls act as air flow directing or deflecting surfaces to direct or deflect the air stream laterally outwardly as it exits from the slot to provide a horizontal discharge pattern.

When the air pattern controller does not block off either side of the cylindrical air flow channel, e.g., the position of controller 28 in the channel 26 of FIG. 2, the air flows through the whole cross-section of the channel. The opposing lips 46, 47 deflect the air stream toward the center and thereby counteract each other. The result is a vertical discharge stream substantially at right angles to the face of the diffuser. For optimum results, the upstream opening of channels 26, 27, defined by the inner edges of lips 42, 43 and 44, 45, is of a width about the same as or less than the width of the respective slots 2, 3.

FIG. 2 shows for purposes of illustration a combination vertical pattern, horizontal pattern. An opposite, twoway, horizontal pattern may be achieved by setting the vane controllers in the position shown in FIG. 6, i.e., with the controllers 28, 29 resting on shoulders 34 of the walls 9 of sections 4 and 5.

The embodiment of FIG. 7 is like that of FIGS. 1-6, except that the side Walls 50, 51, 52, 53 of channels 26, 27 are straight instead of curved and the inwardly-directed lips are straight flanges 54, 55, 56, 57 located at the mouths of channels 26, 27. The lips 54-57 function similarly to the curved surface of lips 46-49. Since other structural parts are similar to the embodiment of FIGS. 1-6, like numerals have been used to designate like parts. The pattern controllers of FIG. 7 are set to provide a oneway, horizontal pattern.

The embodiment of FIG. 8 is a single slot diffuser. It is made from members like diffuser sections 4 and 5 of FIGS. 1-6. The single slot diffuser functions similarly to the diffuser portion provided by one of the channels 26 or 27, and again like numerals designate like parts. FIG. 8 shows a mounting bracket or clip 58 attached to the mounting plates 18, 19, the latter, in turn, adapted to be attached to ceiling members 59, 60 or hanger support rods, wires, etc. (not shown).

FIGS. 4 and 5 illustrate two embodiments for connection of the slot diffusers with air supply ducts. In the embodiment of FIG. 4, the air supply duct is a substantially cylindrical duct 61 made of molded Fiberglas or other sound-deadening or sound-insulating material. The molded Fiberglas duct 61 has a longitudinal slot along one side thereof formed between the pointed tips 62, 63 of the cylindrical Wall of the duct 61. The longitudinal opening in the duct 61 is in alignment and communication with the air passage through the slot difiuser.

The duct 61 is mounted on the upper side of the slot diffuser by means of duct fastener elements comprising elongated plate pairs 64, 67. The plate 64 fits against the inner side of the duct 61 and comprises an elongated metal plate 65 lying substantially fiat against the inner side of duct 61 and an elongated plate 66 seated in the slot 13 and lying against the vertical wall 8.

The element 67 comprises an elongated plate 68 lying against the outer, underside of the duct 61, an elongated plate 69 fitting against the plate 66 and a horizontal lip or flange 70, the outermost edge of which seats against the inner side of the wall 12. The two fastener elements 64, 67 hold the tapered tip 62, 63 of the duct 61 therebetween and also function as the support legs or feet which seat in the channels 13. The diffuser-duct combination so provided is one in which the elongated, substantially continuous air passage through the diffuser is supplied with air from the duct 61 substantially along its length by virtue of the longitudinal slot provided in the duct 61.

In the embodiment of FIG. 5, the air is supplied through a conventional type metal duct, i.e., one of rectanguiar cross-section. The inner wall of the duct 71 may be lined with sound-insulating or sound-deadening material, if desired. The lowerwall 72 of the duct 71' has a longitudinal opening extending the length thereof, said opening being defined by downwardly-depending walls 73, 74. The lower ends of the walls 73, 74 are provided with a reverse bend segment 75, 76, respectively, the latter providing with the lower portions of the walls 73, 74 duct support elements which seat in the channels 13 of the diffuser. The duct-diffuser combination of FIG. 5 also provides a combination wherein air from the duct 71 is fed through the slot diffuser substantially throughout the length thereof through the opening provided by walls 73, 74.

Briefly, the slot diffuser embodiments of FIGS. 9-12 comprise a diffuser face with one or more elongated, air discharge slots therein. Spaced, opposite, elongated, side walls define an elongated air passage or passages communicating with the respective slot or slots. There is an elongated air-deflecting lip or flange along each longitudinal edge of the respective slot or slots, made, for example, by wall portions of the wall forming the face of the diffuser. These lips or flanges are at substantially right angles to the side walls forming the respective air channel or channels and form at the respective downstream side of the respective channel elongated air-deflecting surfaces along the respective longitudinal edges of the respective slot substantially at right angles to the flow direction of the respective air stream of the channel or channels.

At least one, and preferably two, elongated dampers or air-deflector vanes extend longitudinally in the respective channels approximately coextensively with the respective, elongated slot. Each elongated damper or vane is mounted to swing about a longitudinal axis whereby it may be pivoted toward or away from a side wall of the respective channel. Two, side-by-side, elongated dampers or vanes which have convex, outer surface along the respective downstream edges and over which the air flows immediately before exit through the elongated slot are preferred forms for said dampers or vanes.

Referring to FIGS. 9l2 of the drawings, the face of a double slot diffuser 81 has therein a pair of parallel, elongated, air discharge slots 82 and 83. The diffusers of the invention may be made from metal extrusions. The double slot diffuser of the drawing may comprise extrusions 83, 84 and 85 forming the side walls 86 and 87 of the diffuser and a middle wall 88 parallel therewith, the walls 86, 87 and 88 forming a pair of parallel air flow channels 89 and 90.

The side walls 86 and 87 may have flanges 91 and 92, respectively, formed as an integral part of the extrusion along the downstream edge of the respective side wall. When the diffuser is inserted and mounted in a slot in the ceiling or wall, the flanges 91 and 92 lie against the ceiling adjacent to the slot therein.

The walls 86 and 87 each also have at their respective downstream edge a narrow, longitudinal lip or flange 93 and 94 at least substantially coextensive with the respective slots 82 and 83. The lips or flanges are directed inwardly into the channels 89 and 90, respectively, and their upper surfaces form narrow air-deflecting surfaces substantially at right angles to the air stream in the channels substantially at the mouths of the channels (the slots 82 and 83). Air flowing through the channels alongside the respective wall 86 or 87 is deflected by the lips or flanges 93 or 94 into a lateral flow path (shown by the arrows in FIGS. 1042).

The middle wall 88 has at its downstream edge a longitudinal wall 95 substantially coplanar with the flanges 91 and 92. The wall 95 forms lips or flanges 96 and 97 extending from wall 88, respectively, into channels 89 and 90 at the mouths thereof. Wall 95 and flanges 91 and 92 form the face of the diffuser with elongated slots 82 and 83 therein. Air permitted to flow through the channels near the wall 88 is deflected by the lips or flanges 96 or 97 into a lateral flow path.

The walls 86, 87 and 88 may have longitudinal lips 98 near the upstream edges thereof, to which lips may be attached or on which lips may be mounted an air supply duct (not shown). The flanges 91 and 92 each may have a longitudinal lip 99, and the walls 86 and 87 each may have an L-shaped, longitudinal lip 100. These members form a longitudinally-extending T-slot 101 on the lower end of the outer side of each of walls 86 and 87. The T-slots can be used to mount the diffuser on structural members of a ceiling or the like.

In order to selectively control or adjust the air discharge pattern of the diffuser, air-flow-directing means is provided in each channel 89 and whereby the air flowing through each channel may be allowed to flow against and be deflected by flanges or lips 93, 94, 96 and/ or 97. The member or members employed as the air-directing means damper or vane members pivotally mounted in and extending longitudinally in the air channels. The damper or vane members pivot about axes extending longitudinally in the channels, and they may be swung into proximity or actual contact with or away from side walls 86, 87 or 88 of the respective channels.

In the illustrated embodiment of FIGS. 9-12, an extruded, vane-support bar 102, which in transverse crosssection is like an inverted T, is positioned in the upstream side of each channel 89 and 90 approximately midway between the walls 86 and 88 and 87 and 88. The undersurface of the cross-leg of the inverted T, vane-support member, which extends substantially the length of respective channels 89 and 90, has a pair of round, longitudinal grooves 103 and 104, the arc of which is slightly more than 180.

The cylindrical, longitudinal, upstream edges 105 and 106, respectively, of vanes or dampers 107 and 108 snap into the grooves 103 and 104 and are pivotally supported therein. The vanes or dampers 107 and 108 extend substantially the length of the channels 89 and 90. They may be of any suitable shape in transverse cross-section, i.e., flat plates, curvate in transverse cross-section, etc. The best shape for the dampers or vanes is one in which the outer, air flow surface of the downstream portion 189 and 110 of each damper or vane is offset, preferably convex, in a direction toward the center of the channel. This gives a convex, outer surfaces 111 and 112 on each vane or damper over which the air may flow with least turbulence. The vanes may be extruded metal vanes of curvate, transverse cross-section. The friction between the grooves 103 and 184 and the cylindrical edges 105 and 106 of the vanes or dampers is sufficient to hold them in the adjusted position against the force of the air stream.

The walls 86, 87 and 88 may be supported in the illustrated relationship to each other by any suitable means. For example, the walls 86, 87 and 88 and support bars 102 may be attached at their ends to end walls 113 and 114 of the slot diffuser. The end walls 113 and 114 may have, if desired, flange members 115 and 116 lying flush or coplanar with flanges 91 and 92.

The desired air discharge pattern is selected by pivotally positioning the vanes or dampers. The supply air flowing into the upstream sides of channels 89 and 90 is split into two streams in each channel by the vane-support member 102. When the vane or damper 107 of channel 89 and the vane or damper 108 of channel 90 are pivoted against or in proximity to the outer walls 86 and 87, respectively, of the channels, and when the other vanes of each channel are left spaced from the middle wall 88 (FIG. 10), a horizontal pattern from each slot is produced in the form of a two-way, horizontal air discharge pattern. In this adjusted position, the flow of air adjacent the outer walls 86 and 87 of channels 89 and 90 is blocked. The air flows through channels 89 and 90 between the wall 88 and the members 102 and the vanes 108 or 107, respectively. The air is deflected by lips or flanges 96 and 97, and a horizontal discharge pattern results.

In FIG. 11, the vanes or dampers are adjusted so that air is discharged horizontally from each channel in the same direction, i.e., a one-way horizontal pattern. In FIG. 12, there is shown a vane or damper adjustment providing a vertical discharge pattern from channel 89 and a horizontal pattern from channel 90. The vertical pattern results by allowing air to flow between the outer surfaces of both vanes 107 and 108 and the respective side walls of the channel. The lips or flanges 93 and 96 of channel 89 deflect the divided streams of air toward each other as they exit from the slot, and the reunited streams form a vertical discharge pattern, i.e., an air stream flowing outwardly from the diffuser at a substantially right angle to the face of the diffuser. The vanes of channel 90 may be adjusted like those of channel 89 to give a vertical pattern from both slots 82 and 83.

Furthermore, when both vanes 107 and N8 are pivoted into contact with the side walls of channels 89 and/ or 90, vanes may then serve as close-off dampers blocking air flow through the respective channels. Diffusers of the type herein described may have only a single channel and slot.

The vanes or dampers 107 and 108 of the diffuser of FIGS. 9-12 are used to adjust the air discharge fiow direction over a range of 180, i.e., between a horizontal full left pattern and a horizontal full right pattern. The pattern may also be a two-way (left-right) horizontal pattern, a vertical pattern, a combination vertical-horn zontal pattern, or an air flow pattern betwen full horizontal and full vertical. The versatile discharge patterns may be fitted to a wide variety of requirements for air discharge patterns. The vanes or dampers can be adjusted at any time after installation of the difiuser because they are accessible through slots 82 or 83.

It is thought that the invention and its numerous attendant advantages will be fully understood from the foregoing description, the specific forms herein disclosed being preferred embodiments for the purpose of illustrating the invention.

The invention is hereby claimed as follows:

1. In a method for distributing air from a duct through an elongated slot diffuser mounted in the ceiling of a room, said slot difiuser having spaced, opposite, elongated walls defining an elongated air flow channel with horizontal, elongated, inwardly directed, substantially coplanar, spaced lips at the downstream, lower end of said channel, said lips defining in the space therebetween an elongated, unobstructed, horizontal, air discharge slot, the improvement comprising feeding an air stream downwardly into the upper side of said channel, splitting said air stream in said channel into two side-by-side, downwardly-flowing air streams flowing along opposite sides of said channel, impinging one or both of the respective, divided air streams against the upper sides of the respective lips at the downstream ends of the respective sides of said channel, thereby deflecting the respective, divided air stream or streams laterally across said unobstructed slot, and dampering the respective flow volumes of said divided air streams at a proportion between (a) substantially equal flow volumes whereby the laterally deflected, divided air streams reunite at said unobstructed slot and emerge into the upper part of the room in an essentially vertically downward flow pattern and (b) substantially complete blocking of air flow through only one'of said divided air streams whereby the other divided, flowing air stream is vdeflected laterally across said unobstructed slot and emerges into the upper part of the room in an essentially horizontal pattern.

2. A process as claimed in claim. 1 wherein the temperature of the air stream fed into the upper side of said channel is higher than the temperature of the air in said room, and divided air streams are dampered to provide said substantially equal flow volumes, thereby giving said essentially vertically downward flow pattern from said slot into the room.

3. A process as claimed in claim 1 wherein the temperature of the air stream fed into the upper side of said channel is lower than the temperature of the air in said room, and divided air streams are dampered to block off essentially all flow through one of said divided air streams, thereby giving said essentially horizontal air flow pattern from said slot into said room.

4. A process as claimed in claim 1 wherein the inner portions of said divided air streams flow in the vicinity of said slot over a vertically convex surface.

5. A process as claimed in claim 1 wherein the outer portions of said divided air streams flow in the vicinity of said slot over a vertically concave surface.

References Cited by the Examiner UNITED STATES PATENTS JOHN F. OCONNOR, Primary Examiner. 

1. IN A METHOD FOR DISTRIBUTING AIR FROM A DUCT THROUGH AN ELONGATED SLOT DIFFUSER MOUNTED IN THE CEILING OF A ROOM, SAID SLOT DIFFUSER HAVING SPACED, OPPOSITE, ELONGATED WALLS DEFINING AN ELONGATED AIR FLOW CHANNEL WITH HORIZONTAL, ELONGATED, INWARDLY DIRECTED, SUBSTANTIALLY COPLANAR, SPACED LIPS AT THE DOWNSTREAM, LOWER END OF SAID CHANNEL, SAID LIPS DEFINING IN THE SPACE THEREBTWEEN AN ELONGATED, UNOBSTRUCTED, HORIZONTAL, AIR DISCHARGE SLOT, THE IMPROVEMENT COMPRISING FEEDING AN AIR STREAM DOWNWARDLY INTO THE UPPER SIDE OF SAID CHANNEL, SPLITTING SAID AIR STREAM IN SAID CHANNEL INTO TWO SIDE-BY-SIDE, DOWNWARDLY-FLOWING AIR STREAMS FLOWING ALONG OPPOSITE SIDES OF SAID CHANNEL, IMPINGING ONE OR BOTH OF THE RESPECTIVE, DIVIDED AIR STREAMS AGAINST THE UPPER SIDES OF THE RESPECTIVE LIPS AT THE DOWNSTREAM ENDS OF THE RESPECTIVE SIDES OF SAID CHANNEL, THEREBY DEFLECTING THE RESPECTIVE, DIVIDED AIR STREAM OR STREAMS LATERALLY ACROSS SAID UNOBSTRUCTED SLOT, AND DAMPERING THE RESPECTIVE FLOW VOLUMES OF SAID DIVIDED AIR STREAMS AT A PROPORTION BETWEEN (A) SUBSTANTIALLY EQUAL FLOW VOLUMES WHEREBY THE LATERALLY DEFLECTED, DIVIDED AIR STREAMS REUNITE AT SAID UNOBSTRUCTED SLOT AND EMERGE INTO THE UPPER PART OF THE ROOM IN AN ESSENTIALLY VERTICALLY DOWNWARD FLOW PATTERN AND (B) SUBSTANTIALLY COMPLETE BLOCKING OF AIR FLOW PATTERN AND (B) SUBSTANTIALLY COMPLETE STREAMS WHEREBY THE OTHER DIVIDED, FLOWING AIR STREAM IS DEFLECTED LATERALLY ACROSS SAID UNOBSTRUCTED SLOT AND EMERGES INTO THE UPPER PART OF THE ROOM IN AN ESSENTIALLY HORIZONTAL PATTERN. 